USGS puts the kibosh on '1000 year flood' and 'caused by climate change' claims over South Carolina flooding

From the “looks like a win for skeptics” department. USGS publishes new information that quashes widespread media and activist claims that the flood in South Carolina was caused by climate change; nor was it a “1000 year event” as many have called it such as USA Today:

1000-year-flood

USA today headline from their website. Sounce: http://www.usatoday.com/story/weather/2015/10/05/south-carolina-flooding-climate-change/73385778/

From the USGS: Flood Information website:

Dr. Robert Holmes, USGS National Flood Hazard Coordinator, takes some time to discuss and answer some hot issues related to the flooding in South Carolina.

Is this flooding in South Carolina truly a 1000-year flood?

While this certainly was a catastrophic flood with lots of damage and tragic loss of life, USGS provisional data and preliminary analysis show NO indication that a 1000-year flood discharge occurred at any USGS streamgages. However, based on that analysis, it does appear that the USGS streamgage on the Black River at Kingstree, SC and the one on theSmith Branch at Columbia, SC both measured peak floods in the neighborhood of a 500-year flood. Currently, there appear to be a few more streamgages experiencing a 25-year to 50-year flood, but the majority of USGS streamgages had flood peaks that were less than 10-year floods. USGS will have more accurate estimates of the flood probabilities out in the coming months, as the engineers and scientists in South Carolina take time to do more careful analysis of the statistics.

I heard that the river flow through downtown Columbia was 4 times the historic maximum; maybe that was close to the 1000-year flood?

The provisional peak flood flow that USGS measured for the Congaree River in Columbia was 185,000 cubic feet per second (cfs) on Sunday, October 4, 2015. The maximum recorded in history was 364,000 cfs in 1908, which is almost double what was experienced in this current flood.

In the 1930s, though, reservoirs were built in certain parts of the Congaree watershed upstream of Columbia, which makes a flood of 364,000 cfs unlikely. However, even in the 75 years since the construction of those reservoirs (see the peak record here), there have been floods that approach the 2015 flood. For example, in 1964 the peak discharge was 142,000 cfs, and in 1977 the peak discharge was 155,000 cfs.

So, if only the data from last 75 years are considered, this flood is the largest in that period, but not four times the historic maximum.

Why do you think people have been calling it a 1000-year flood?

When USGS uses terminology like “1000-year flood,” it means that, statistically speaking, a flood of that magnitude (or greater) has a 1 in 1000 chance in any given year. In terms of probability, the 1000-year flood has a 0.1% chance of happening in any given year. One must keep in mind a 1000-year flood value is a statistical value based on observed data.

Although the USGS streamgage data in South Carolina does not seem to indicate a 1000 year flood, the amount of rainfall that fell over a 2 to 3 day period (greater than 16 to 20 inches in some locations) had, according to the National Oceanic and Atmospheric Administration (NOAA), a statistical probability of occurrence of 0.1% or 1 in 1000 chance. So, rather than someone saying this was a 1000-year flood, it is more accurate to say that “statistically speaking”, the rainfall that fell was a 1000-year rain storm, although it did not result in a 1000-year flood.

How can we have a 1000-year rain that does not result in a 1000-year flood?

It comes down to a number of factors, including the pattern of movement of the rain storm in each particular watershed, the conditions of the soil and plant matter on the ground in the watershed, and the timing of rain storm in one watershed versus other watersheds, among other things. An example would be that ground that is saturated before 1 inch of rain fell would result in more water going into the stream that if the ground was dry and could soak up more of the rain. Also, less water will runoff into streams from 1 inch of rain falling in the summer with the trees full of leaves versus the winter when there are no leaves to intercept the rain. This is all the science of hydrology, which is the study of the movement and distribution of water on the earth. Of course, in South Carolina, many of the watersheds have streams that are regulated by dams.

Is this flood due to climate change?

USGS research has shown no linkage between flooding (either increases or decreases) and the increase in greenhouse gases. Essentially, from USGS long-term streamgage data for sites across the country with no regulation or other changes to the watershed that could influence the streamflow, the data shows no systematic increases in flooding through time.

A much bigger impact on flooding, though, is land use change. Without proper mitigation, urbanization of watersheds increases flooding. Moreover, encroachment into the floodplain by homes and businesses leads to greater economic losses and potential loss of life, with more encroachment leading to greater losses.

Why do the values for the 100-year flood seem to change with every flood?

The amount of water corresponding to a 100-year flood, a 500-year flood, or a 1000-year flood is known as a “flood quantile”. For instance, on a given river, the flood quantile corresponding to the 50-year flood might be 10,000 cubic feet per second (cfs) or the flood quantile corresponding to the 100-year flood might be 15,000 cfs. The estimates of the flood quantiles (corresponding to various probabilities) are made from using actual data collected at a site in a statistical analysis.

So, for a particular river, USGS would collect data over time; determine the largest flood in each year and then run statistical analysis on that data. Now, the more years of data available, the more accurate the estimates for the various flood quantiles (the floods corresponding to the 50-, 100-, 500-year, etc). For example, if there are 40 years of data, that would yield a better estimate of the 50-year flood than if only 25 years of data were available. Moreover, if only 50 years of data exists, statistical models will do better estimating the 10-year flood quantile than the 100-year flood quantile.

As more years of data become available, the estimates become more refined, which can result in the quantiles changing. An example in the Southeast United States is the Broad River at Carlton, GA. That watershed had a wet period, with larger annual peak floods, from the late 1800’s to 1920, followed by a drier period since that time (at least in terms of flood peaks). The statistical analysis for the entire period (late 1800s to 2014), which includes the wet years prior to 1920, results in an estimate of a 100-year quantile that is 40 % higher than the one using the data from just 1920-2014.

But it seems like the 100-year flood is getting larger through time at a site near me, so you are saying that this is not necessarily from climate or land-use change?

Climate variability (dry cycles to wet cycles) plays a large role. There is a large amount of uncertainty around the flood quantile estimates (the value of discharge corresponding to the 100-year flood), particularly if there isn’t a long record of observed data at a stream location. For example, if there is only 25 years of data and a statistical analysis was done on that data to estimate the 100-year flood, uncertainty around the estimate would be quite large. It can look like flooding at that particular location is getting worse if there are 2 or 3 floods in a short period that exceed that estimate of the 100-year flood. However, if there were 700 years of data, it might show that what had been called a 100-year flood when there was only 25 years of data was really only a 10-year flood.

I would like to dig a little deeper into the meaning of 100-year flood, can you tell me more?

Instead of me doing that here, let me point you to something on the web that I prepared several years ago on this very subject. I titled it “100-Year Flood—It’s All About Chance”. You can see what I have said by going to http://pubs.usgs.gov/gip/106/.

Source: http://water.usgs.gov/floods/events/2015/Joaquin/HolmesQA.html

h/t to Marc Morano of Climate Depot

Note: about an hour after publication, the first paragraph was corrected for a typo and to read more clearly on the intended meaning.

Advertisements

115 thoughts on “USGS puts the kibosh on '1000 year flood' and 'caused by climate change' claims over South Carolina flooding

  1. Better check your first paragraph, Anthony. Besides the small typo, I don’t think the sentence is what you intended to express.

    • It is still early Saturday AM in California….
      Regardless of the USGS claim, the activist media got their rimshots in during the flood and no one amongst them will feel the need to correct the record. That is what WUWT & Climate Depot etc are for.
      BTW has Barbara Boxer quoted the 1000 year Climate Change Flood yet?.
      I am still waiting on the 100 year rainfall event. One thing. If there was a flood 1000 years ago (buying into the CAGW twisted notion of statistics) and there was no industrialization; rather, a medieval warming period 1000 years ago, can we not use this non-event to hype non-warming, like the medieval warming period, and thereby prove there is no warming now because there was warming then?
      Are you confused? Yes, on this site you are confused but I am appealing the the reasoning of the global warmists and their tortured lens of cause and effect.

      • If you look at 1000 different regions on Earth, then statistically speaking, one of them should have a 1000 year flood, or a 1000 ARI every year. It’s got nothing to do with the climate 1000 years ago.

      • Quite possible, provided the events are random so in that case I would draw a distinction between probability and statistics.

    • “…that quashes widespread media and activst claims that the flood in South Carolina had nothing to do with claime change…”
      So the flood was caused by climate change then? I’m pretty sure media and activists are not claiming that the flood had ‘nothing’ to do with climate change. Just the opposite.
      Mods, I understand that mistakes happen, but why is it so hard to correct a mistake that was pointed out hours ago? There are also two misspellings in the same sentence of the first paragraph.
      [Reply: Fixed now. It’s impossible to read every comment on every thread, and it’s Saturday. Moderating is not the only thing we do. But thanx for pointing it out. ~mod.]

  2. It appears the NNN-Year flood is a useless descriptor for the purpose for the same reason calling Sandy Kofax a 200-year baseball pitcher is nonsense. Incarcerate anyone who uses such terms and prosecute them under RICO laws for inciting fear in people with poor math skills.

    • FINALLY – someone from USGS talking like an real life honest-to-god scientist. I feared that species had become extinct, perhaps there is hope it may return.

      • Currently, there appear to be a few more streamgages experiencing a 25-year to 50-year flood,…

        Don’t land use changes affect how much water runs off the land and into the rivers and streams. An example is concreted land and roads near streams and rivers. Am I on the right line of thinking here?

        Detection of changes in streamflow and floods resulting from climate fluctuations and land use-drainage changes
        http://link.springer.com/article/10.1007/BF00140354

      • An answer to Jimbo at 12:37
        Geological Survey Circular 554
        Figure 1. Hypothetical unit hydrographs relating
        runoff to rainfall, with definitions of significant parameters.
        http://pubs.usgs.gov/circ/1968/0554/report.pdf
        by Luna B. Leopold
        ______
        Note that the rainfall is usually shown as a bar chart while the flows are shown as a continuous line. I’ve seen “period of rainfall” shown as a continuous line but ti seems less common. Folks use the phrase “storm hydrograph” so a search on that using “images” will work.

      • Jimbo, that’s why the flood zones are updated every 20 years or so, to account for this. It’s an estimate of future flooding, not a historical review.

      • Thanks for the replies.
        Let me put it another way. Let’s assume for a moment there were NO man-made structures or humans in North or South Carolina – would it have been a 1,000 year or 500 year flood? How would the land have handled the flood waters with no pavements, roads, built-up areas etc?
        What gets me is the hint that this [insert years] flood is down to greenhouse gases ‘climate change’. That’s all.

    • It’s not a perfect or an exact measurement. However, it’s a useful estimate of risk and a valid tool for describing the rarity of an event. When used in it’s proper context for it’s proper purpose (describing the rarity of a certain level of flood for preparation and insurance purposes), then it is good.
      For example, a 10 ft flood of the Mississippi could be huge. It could be nothing. I truly don’t know. However, if you describe it as an annual flood level, I know what it is and am willing to mock people whose homes were flooded in it. However, if it is a 50 year flood, then it is surprising but not shocking. Floods occurring outside the 500 year floodplain are shocking.
      Just because something is misused does not mean it’s invalid.

      • How would you like to make your eyes bleed—–http://uli.org/ . I’m going to a meeting were a VP of Sustainability is going to speak. Instead of making a complete fool of myself can anybody offer some poignant questions if there is a question & answer period?

    • The article’s heading paragraph should be corrected thus:
      “USGS publishes new information that quashes widespread media and activst claims that the flood in South Carolina had nothing something to do with claimeate change,”

  3. Shout from the rooftops
    USGS research has shown no linkage between flooding (either increases or decreases) and the increase in greenhouse gases.

    • Yes, but the USGS consists of geoscientists – what would they know? They aren’t climate scientists!

  4. Looks like Dr. Holmes is a professional and knows his stuff. Sure hope he doesn’t get fired for not singing the Obama party line!
    BTW I use the USGS stream gauge data all the time. It’ a great site with lots of useful features.

    • USGS, under the Dept of Interior, currently has career USGS acting Director and Asst Directors, limiting direct political control over its message. So Dr. Holmes will likely get a nastygram from the Obama political appointees that run the Department of the Interior. Sally Jewell, a banker turned REI CEO, runs the Department, with a “staph infection” of Obambots around her, will have emails from WH staffers now telling her to get USGS “on message.”

      • Thanks for that info Joel…even though it offends me that this is the case.
        Seriously…it hurts my feelings!

      • Sad, every agency has become infected, even the military, intelligence, IRS, and secret service thanks in part to a complicit media.
        “Any dictator would admire the uniformity and obedience of the U.S. media.”
        Noam Chomsky

      • Indeed, Dr Holmes is a public servant and if I understand the US system public service system appropriately, he has recourse. Sally Jewel is not a public servant and is not held to the same standard as Mr Holmes. However, it’s illegal for her to intimidate him into lying.

    • Knute,
      The political hacks running Obama’s agencies merely have to keep inconvenient voices and views silent with warnings not to talk about their work or views that contradict the “Message.”
      As for “staph” or “staff”, I meant used the correct word for my meaning… maybe I should have capitalized it and italicized it, as in Staphylococcus aureus, a bacterial infection which can cause skin boils. That is a metaphor that captures Obamabot hacks at work.

  5. Thanks for posting this, Mr. Watts.
    It’s gratifying to see USGS debunk some of the misinformation regarding the SC floods. Most people don’t understand that flood terms such as 50-year, 100-year, 1000-year are based on statistical applications to observed data. As also explained, there’s a difference between a 100(0)-year rain and a 100(0)-year flood.
    As a professional land surveyor, it’s challenging enough to determine actual elevations without trying to explain the hydrology and statistics, for which I lack the education and experience.

  6. Although the USGS streamgage data in South Carolina does not seem to indicate a 1000 year flood, the amount of rainfall that fell over a 2 to 3 day period (greater than 16 to 20 inches in some locations) had, according to the National Oceanic and Atmospheric Administration (NOAA), a statistical probability of occurrence of 0.1% or 1 in 1000 chance.

    Climate variability (dry cycles to wet cycles) plays a large role. There is a large amount of uncertainty around the flood quantile estimates (the value of discharge corresponding to the 100-year flood)

    So just what period are NOAA using to determine the probability of a 1000y event and what is the uncertainty on that probability figure?
    Clearly this is based on extrapolating an assumed statistical model for the probability distribution of storm intensity WAY out into the tail of the assumed distribution fn. where no data exists, since they don’t have 1000 , 500, or even 200 years of storm data.
    Kudos to Dr. Robert Holmes for an objective scientific approach and getting as near as he politely could to saying where we should look for the BS merchants on this.

    • You are looking at this wrong. The floodplain is a measurement of risk, not of history. As they describe in the article, the 100 years and 500 year floods are based on the most recent data available as wet periods and dry periods change the chance incredibly.
      Look at the 100 year floodplain as “we estimate that there is a 1% chance that this region will flood in a year”, and it makes a lot more sense.

      • How can it not be history? If you look at the flood plain maps, all the 10-year events should fall (mostly) within the 10-year flood boundary, assuming you have some reasonable (say 50-100 years) history. The 50-year events may be more nebulous (assuming you have any) and the 100, 500, and 1,000 year boundaries are going to be statistical guesses. There is no way the floodplain can be a measurement of risk without also being a reflection of history.

      • DJ, what I was attempting to say is that it is a short term prediction that is based on multiple things. The most important thing to note is that during wet periods, the flood plain is raised, and during dry periods, it is dropped. It also attempts to adjust for land use changes. After a series of wet years and construction projects, the top of the 100 year floodplain may not have flooded in 300 years, but the situation has made it more likely for it to flood.
        It is an estimate of future patterns that is partially based on history. It is not and should not be used as a measurement of history in and of itself.

    • Please note that the good Doctor is talking about TWO event/probabilities; one is a 1,000-year RAIN and the other is a 100-year FLOOD. Just because you get a 1,000-year rain doesn’t mean you’ll get a 1,000-year flood

  7. I would not mind betting that the 0.1% ( 1000y ) figure is the ‘may be as much as limit of a fairly large uncertainty range on the fitted probability. As usual they hide the uncertainly under the carpet and state it like solid fact. You’d thin they have watershed data going back 2000y ! Maybe they have a tree-ring proxy for that too. 😉

  8. More Climate Porn.
    The offspring of Chicken Little and the Boy Who Cried Wolf… doing acid. The average reader / viewer is growing immune to the hyperbolic drumbeat as the Paris COP 21 approaches.
    Not holding my breath for a “mea culpa”(let alone a retraction) by USAToday.

    • How about that Weather Channel? They are supposed to be professionals, and this is their only business.

  9. the amount of rainfall that fell over a 2 to 3 day period (greater than 16 to 20 inches in some locations) had, according to the National Oceanic and Atmospheric Administration (NOAA), a statistical probability of occurrence of 0.1% or 1 in 1000 chance.

    somebody with some time may want to dig out the NOAA data for SC or Colombia, or wherever the hype-centre [sic] of this event is and do a histrogram plot of the number of events in in each bracket of rainfall.

    • That would be a very interesting read. I wonder what area the rainfall is averaged over to generate their metric? Clearly, if the rainfall took place over an area of say one square mile and was averaged over the entire state, it wouldn’t be impressive at all. Likewise, I doubt that measurements are being taken at the per acre level either.

  10. I think it is more likely a 100 year encroachment into the floodplain by homes and businesses.
    Still not sure how a 1 in 1000 chance in any given year of a certain level of flooding is proof of anything other than there is a 1 in 1000 chance in any given year of a certain level of flooding.

    • Right, and heavy rain that stays in one place for several days straight does not happen every day…but it does happen.

  11. Two individual streamgauges appeared to show in the region of 500 year events.
    But the majority did not.
    The question and the analysis should ultimately be aimed at asking whether the event as a whole was unprecedented in magnitude or scale, or that it should under normal conditions be exceedingly rare.
    By even mentioning individual streamgauges we are falling into the trap of increasing the number of “events”.
    If I tell you that I threw a dice and obtained 4 consecutive 6’s, then this is only notable if I sampled only this one event. It is then notable and may perhaps lead us to suggest that the dice may be loaded.
    If you then discover that I spent all week throwing the dice, and waiting for a remarkable occurence then the event is now unremarkable.
    In the modern search for “climate extremes” we risk falling for the same simple flaw in thinking.
    We are looking into a chaotic system at finer and finer detail, and thus continually raising the number of events which may appear to be suspect, weird, unprecedented, “1000 year”, or whatever.
    But, when you look deeper into the Mandelbrot, you see more Mandelbrot.
    It’s turtles all the way down.
    Sampling at finer detail will APPEAR to present us with MORE extremes.
    But that is an artifact of the act of looking harder and at more stuff.
    Here I am in Somerset in the UK, hearing about an individual stream guage in Carolina.
    This is definitely due to a phenomenon called “extreme weather”, or perhaps “extreme weather awareness”.
    But only inasmuch as “extreme weather” is a modern social phenomenon which can lead a person at a computer in Somerset to fixate his attention on an individual stream guage in Carolina.
    Meanwhile, graphs of rainfall averages, almost invariably show no distinct or concerning trends.
    If the rain in “extreme events” is falling heavier, then how does the rain at all other normal times know that it needs to fall proportionally less heavily, in order to compensate for the heavy downpour?
    This makes no sense.
    I am currently inclined to conclude that the whole thing is a delusion.

    • Sort of liking watching a Lava Lamp for a few weeks and getting excited what the blobs sometimes get bigger or smaller than average.
      The atmosphere is a very complicated Lava Lamp, in a manner of speaking. Certain time lapse videos of Earth imagery are strikingly similar in appearance.

      • Yeah, and, on top of this, like taking a copy of the Guinness Book of Records and then making the intriguing observation that the extreme records listed seem to be increase in frequency towards the date of publication.
        (OMG – a TREND, in the historical record, of records. Definitely PROOF of something. So we must find the physical CAUSE).
        Then deciding that this worrying phenomenon should be investigated systematically by spending more time and money on documenting record breaking things and events.
        Houston, we have a problem… 🙂

  12. I used the mischaracterization of the SC flood along with the graphic visual images (see my comment on previous post) as an illustration of all these false narratives that all go to increasing public power to redesign the economy and plan society. http://www.invisibleserfscollar.com/disguising-the-rise-of-the-oligarchs-via-competencies-new-values-a-thinking-curriculum-and-other-false-narratives/
    The post includes links to iclei reports where they are bragging about how most of the UN’s Vision 2020 agenda our governments have signed us on to will have to be carried out by local governments. After all they have the most control over people, places, and especially students. The UN has even developed the term ‘localization’ to describe the local administration of its global agenda.

  13. ” …in South Carolina, many of the watersheds have streams that are regulated by dams.” To what extent do the existence of these dams influence the readings on the stream gages?

    • If I’m not mistaken, a dam can slow down the volume of water going down stream. Unless the reservoir fills up and overflows, the surge from upstream rainfall is buffered and the dam can provide a more controlled release.

    • Up to 100% influence.
      If the Corps of Eng shuts the “spillway” gates off the stream flow will decrease, … except in rare events.
      I live about 2+ miles downstream from a Flood Control Dam and my backyard borders on the outflow river channel. There was an extreme rain event in 1985 and the Corps shut the outflow of the Dam off ….. but there was so much rainwater flowing into the river channel via tributaries downstream from me that the river behind my house was actually flowing upstream toward the Dam.
      I live about 2+ miles downstream from a Flood Control Dam and my backyard borders on the outflow river channel. There was an extreme rain event in 1985 and the Corps shut the outflow of the Dam off ….. but there was so much rainwater flowing into the river channel via tributaries downstream from me that the river behind my house was actually flowing upstream toward the Dam.
      Most flooding events are not caused by excessive rainfall … but because of the restricted “flow capacity” of the river channel. When rainfall amounts exceed the flow capacity then flooding results.

    • A few years ago Brisbane (in Oz) suffered from a dam release during a high rainfall event that caused severe damage. Of course, climate change was the first culprit until an investigation uncovered that the dam was supposed to be there for flood containment but they had allowed it to fill and there was insufficient room to hold back the water so they had to release it.
      Unsurprisingly, a lot of the damage was to buildings (residential and industrial) that were built on the flood plain next to the river.

  14. US Geological Survey publishes National Streamflow Statistics (NSS) for estimation of n-year flood flows on watersheds without stream gages. The link:
    http://water.usgs.gov/software/NSS/
    Note that NSS replaces the old National Flood Frequency (NFF) program.
    For the inquisitive, Bulletin 17B explains the statistics behind much of this. Link here:
    http://water.usgs.gov/osw/bulletin17b/bulletin_17B.html
    FEMA applies the theory to its statement that there is roughly a one-in-four chance of a “100-year” flood hitting a home during a 30-year mortgage.
    http://www.fema.gov/pdf/floodplain/nfip_sg_unit_3.pdf
    “The term “100-year flood” is often misconstrued. Commonly, people interpret the 100-year flood definition to mean “once every 100 years.” This is wrong. You could experience a 100-year flood two times in the same year, two years in a row, or four times over the course of 100 years. You could also not experience a 100-year flood over the course of 200 or more years.”

  15. We see frequent flooding at the Mississippi and Illinois confluence and the buildings in the towns along the rivers have been repeatedly inundated since pioneer days, yet folks stay, and build higher stilts or watertight concrete vaults under their houses. A friend who lives in the nearby tourist haven town of Grafton IL says the town survives by “ignorant tenacity”.
    By the way, many back roads here have fords (low water crossings) and a gully-washer can deposit a 100 ft oak tree across the road in little or no time. Makes emergency services difficult

  16. Two points that I don’t see in the analysis.
    First, there is the statistical fallacy of assuming a normal distribution, or log-normal or exponential distribution for rain fall amounts over time. These nice mathematically clean distribution definitions serve as a first approximation, but they are not “The Truth”. As explored in “The Black Swan”, Fat Tailed Distributions are common in reality and thus it appears that any noteworthy event has a much larger probability in a fat tail distribution than the standard approximating distribution would indicate. The failure is in the choice of models to describe uncommon events.
    Second, let us assume that the SC floods really were a 1000 year event — for SC. South Carolina is about 32,000 mi^2. The lower 48 states is almost 100 times bigger (2.96 E+6 mi^2). Statistically then, we should expect a 1000-year flood somewhere in the lower 48 states about every 10 years.
    Maybe we should have insurance companies tell us about the frequency of weather events. But then again, that’s how they make a profit.

  17. “Is this flood due to climate change?
    USGS research has shown no linkage between flooding (either increases or decreases) and the increase in greenhouse gases. Essentially, from USGS long-term streamgage data for sites across the country with no regulation or other changes to the watershed that could influence the streamflow, the data shows no systematic increases in flooding through time.”
    Let me get this straight. AGW (aka : CO2) has no effect on the hydro-logical cycle (thus no increase or decrease in atmospheric water vapor) nor does it have any effect on the convection cycle. And USGS admits this?
    Correct me if I am wrong but isn’t that a base premise of CAGW? So they admit its a lie in a round about way… hmmmmmm
    I can hear alarmist heads exploding from where I live…

    • Funny how they took empirical evidence, reported it truthfully, and it disproves their pet theroy in one fail swoop… Got to love it!

    • The difference: USGS is made of engineers and surveyors. They have first hand experience with the information, and they are responsible to their data and their data alone. Plus, there is strong protection from political influence as it is not a plum job and their decisions are important to the insurance industry, giving them strong independence requirements.
      However, don’t read too much into it. It is only what they said, no more. There have been no changes in flooding due to climate change.

    • The year was 1972. The concern was global COOLING. Hurricane Agnes dropped up to 20 inches of rain in Pennsylvania and we experienced extreme flooding along the Susquehanna.

  18. Is there any justification for assuming the extreme tails of a precipitation event are well described by a normal distribution (or a known distribution for that matter)? If not, describing a flood as 1 in a 1000 based on 100 years or less of data is nonsense…

    • It is unlikely that these things live in a L2 universe. By that I mean that the second order sample statistics will not converge but will rather diverge the more data you measure. Always remember Hurst studied the flooding of the Nile and simulated it with a deck of cards.

  19. Dr.Holmes sounds just like most of the USGS hydrologists that I worked with for over 30 years.
    A decent person trying to find the truth, and trying to explain it to others in the clearest manner in which he can.
    Score one for the good guys!

  20. I could not resist the mental image of your cartoonist friend jotting a picture of a group of activist protesters shouting ‘denier’ at a USGS streamgage robot and calling for the manufacturing company to be brought up on RICO charges.

  21. What none of the media has taken into consideration, was that we had almost two solid weeks of rain across the state prior to the inflows from the hurricane. Our soil was already close to saturation with localized flooding already occurring.

  22. The climate liars had this one well covered with their disinformation campaign.
    I am surprised that I can still be surprised by how wrong so many can be about so much.

    • I couldn’t resist dropping this USGS article into the cesspool of Think Progress. The Rommulans had been doing their usual number on this event. I am anxious to see their responses.

      • http://nyp.st/1LuCCyY
        I hope you can open the above link. It’s an Op Ed concerning Russia in the Middle East. I linked to it because the conclusion is similar to what scientists should consider concerning the intent of warmists.
        Stop trying to only fight bad science w good science. Bad science wants to secure its interests. They will continue to do so via hyperbole and alarmism.
        What other tools have you found useful other than boringly pounding the table about good science ?

  23. Indeed, the equivalent of an almost retraction.
    It’s also an opportunity to see what works in the debate.
    The link below is to one of Mr Steve Schneider’s last public appearances. He died a few weeks later (RIP). It’s a few years old but becomes more valuable as I watch it. As the years go by, the emotion of the moment becomes more detached, I am more liberated from my immediate biases.

    41:05 begins a vivid clue into the difficulty of publically debating CAGW. Media catering to choices of extremes to garner viewer interest, and a scientist discussing probability and how it reflects on their presentation of the risk.
    Thanks for watching it.
    Science found “x”
    Risk assessors determine “y”
    Risk managers debated “z”.
    Profiteers ran free.
    Now compare that moment with the concept of media latching onto doom or euphoria to garner interest. 1000 year flood ? A continuance of the attention grabber.
    Media is supposed to sell an interest in stories. Some media hold to a higher standard, others dont. In a world where competing for attention has become other worldly, they have their work cut out for them.
    On the other hand, science is trapped in a knot of a riddle. In order to regain the purity of what it is supposed to be, the field is very likely going to have to undermine its own appeal. It will have to admit to the fact that it is nothing more than an ATTEMPT to reduce uncertainty and fraught with the humbling reality that sometimes it doesn’t even know what questions to ask. Ah, but it can replicate the data for the question that may have nothing to do with the issue that is being discussed.
    Despite the challenge, Im pulling for science.
    Learn from this minor flood history correction. Perhaps acknowledging your own weakness as a field allows you the ability to undermine the bigger perversion of CAGW. You’ll survive. More humble, more centered back on the scientific method and da peoples may collectively learn a thing or two.
    This post is too long. Sorry about it. I’ll work on cutting the point down.

    • Thanks for the link Knute. That gives me a much better idea of what Schneider was about.
      He answers most questions well. It’s also pretty clear the educational reach of this web site in the questions he was getting thrown !!
      The one bad response that he got away with was his bath-tub analogy. As the water gets higher the same drain whole will evacuate more water, not the same amount as he claimed.
      The knowledgeable questioner pulled him up on this and mentioned to key word “homoeostasis” but this key point got lost in the tight schedule of a TV debate.

      • I agree that he came across as a more reasonable scientist than this statement attributed to him:
        ” On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but — which means that we must include all the doubts, the caveats, the ifs, ands, and buts. On the other hand, we are not just scientists but human beings as well. And like most people we’d like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broad based support, to capture the public’s imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This ‘double ethical bind’ we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both.”
        Also his apparent frequent reference to the models and the IPCC lead me to wonder if he was too dependent on questionable science in his replies hoping the audience was uninformed.

    • Knute, I appreciate what you’re getting at. It is critical that we understand the end game and how it is so devoid of environmental design. Appealing scientifically to the political machine that underpins IPCC is like expecting a fish to dig episodes of Bob Newhart. And good people like LMofB are right with you in activating political counter measures. But I think you are underestimating the political power inherent in the public discourse. A tide has turned, and largely due to the public’s exposure to the potential that CAGW is a NULL hypothesis. We have to falsify wild claims to the enth degree in order to humiliate the CAGW machinery, and that how numbers grow. Education bolsters against being co-opted down the road.

    • You cant, but that’s not the objective. The objective is to get attention. Take this instead from a polling request I received this morning,
      “Donald Trump is clearly the most polarizing figure in the upcoming 2016 election. Whether you love him or hate him, he’s gathering massive amounts of media attention.”
      ‘he’s gathering massive amounts of media attention’.
      And that’s the prize.
      Get attention.
      Good science is boring.
      In the court of public appeal, your never going to compete and win with an alarmist by denying the cause for alarm exists.
      Now consider a sexy, wealthy medical researcher gets up in front of the BBC and makes a total mockery of some popular drug. Now that’s news that shifts the debate. It stabs at the soft underbelly.
      Do the same with perhaps a rocket scientist who explains how we are just really fortunate that thru trial and error (not models) we get to blow alot of stuff up before we successfully shove that big thing into orbit. Shock value.
      Then find a an equally attention grabbing climatologist and have them rip a giant hole thru the uncertainty of their field and you begin to get people attention.
      Headline reads
      “Famous panel of scientists warn the world not to trust them as much as they do”
      Would you watch it ?

  24. I get the impression that the initial reporters simply wanted to bandwagon their favorite subject. The rainfall was heavy, but the stream gauges were inconsistent in what they reported. Surely a reporter would have asked the local authority what the go was. Instead they jumped the gun (shark) and reported an exaggerated version of the worst of the gauge reportage.

      • Knute, like you I came at this from a polical understanding. I get the gamesmanship, the clickbate, the tools of statecraft. And i tried to unhand the fear campaign from that angle. But I need to be able to meet the gatekeepers in debate and crush them with the evidence. The strategy is to take out the foundation. Asking voters to fund a NULL hypothesis will seem silly.

        • The ship of argument over CAGW is the distraction. And so you win the morale victory of being right but not in time for them to have gained momentum in wealth transfer.
          They will get their carbon tax.
          Have made money on alt schemes.
          Picked up sizable positions in depressed fossil assets.
          Warming won’t come.
          The climate will cool.
          You will be proven right.
          The tax will go away.
          We will buy fossils from them.
          They’ll write a book about this in 100 years.
          Sure, fight the battle of good science. It will matter someday when science matters again, but in the meantime you have very few options left to stop them. Pounding the table al la Cruz of being duped is good theatre … that’s all … off Broadway at best.

          • I’m a Canadian, the ruling party will decide to fund the IPCC and to set up a carbon tax..or emissions tax. If the federal Conservatives win we avaoid the tax, if they don’t, cue the sucking sound. This is a well concieved plan to set up the tax base for global governance. And through downward pressure more countries will sign up. That ship is sailing. But the political capital is not in stopping the ship, its in letting it sink.

          • OvG
            “I’m a Canadian, the ruling party will decide to fund the IPCC and to set up a carbon tax..or emissions tax. If the federal Conservatives win we avaoid the tax, if they don’t, cue the sucking sound. This is a well concieved plan to set up the tax base for global governance. And through downward pressure more countries will sign up. That ship is sailing. But the political capital is not in stopping the ship, its in letting it sink.”
            I cut n pasted cause I wanted to get your pov.
            You opine that the ship has sailed, the tax is on its way and global governance is en route ?
            You are hopeful that the federal Conservatives will save Canada but realistic that they will likely be sucked along as more countries sign up ?
            My tidbits for your pov. ALL current political parties have their hand in the till. They either are in it overtly or positioned behind the scenes for when it comes. Hedging their bets … waiting to see to what degree the UN pulls off the scam. Federal conservative victory won’t matter because they are probably sold out and if not Canada doesn’t really pull enough weight to matter (I like Canada btw and have a place there).
            Despite knowing that the inevitable is coming you are committed to exposing the ruse. Admirable from an integrity pov and the future of science, but ineffective for this variety of bulletless warfare. The IPCC has already told you it is not about climate change so why continue to belabor the point ? They already told you so.
            They already told the world and the world yawned. In a bizarre twilight zone moment, the IPCC has admitted their cause is not CAGW and nobody bothered to stop and listen. Why ?
            I opine that few took CAGW seriously in the first place. Yeah, they liked that it cracked the door open for new whiz bang energy and free grant money. New careers. Puppies for the girlfriend and cars that whirl. A pretty end where the means we’re corrupt, but so what. I’ve easily heard hundreds of times that “so what, it’s for a good cause”.
            I think that’s why they were easily seduced.

          • Here a marvelous little site that does much better than I can concerning the status of the carbon tax. The UN does it for you while sprinkling in a Mann here and a pope there.
            http://www.carbontax.org/blog/
            The mob hates one thing more than others. They will blindly follow you here or give up their freedoms there. And, they will do it rather cheaply. But, if the mob knows that you plan to take away a painfully large portion of their earnings they push back.
            So what do people think this will cost the average first tier nation citizen ? (yearly)
            5%
            10%
            15%
            Got any cites ?

  25. Although the USGS streamgage data in South Carolina does not seem to indicate a 1000 year flood, the amount of rainfall that fell over a 2 to 3 day period (greater than 16 to 20 inches in some locations) had, according to the National Oceanic and Atmospheric Administration (NOAA), a statistical probability of occurrence of 0.1% or 1 in 1000 chance.
    I don’t know how they work their statistics out, but Hurrican Floyd dropped 17″ on Myrtle Beach in just two days in 1999.
    https://notalotofpeopleknowthat.wordpress.com/2015/10/05/south-carolina-floods-a-thousand-year-rainfall/
    The highest official figure I have seen this year is 14″ in three days at Charleston.
    While there have been unofficial reports of higher rainfall in a few outlying localities, this is always likely to happen. It would have been extremely unlikely that the Myrtle Beach official measurement was the highest anywhere in the State on that occasion.
    Clearly it is a nonsense to claim 1 in 1000, when a similar event occurred just 16 years ago.

  26. “USGS puts the kibosh on ‘1000 year flood’ and ’caused by climate change’ claims over South Carolina flooding.”
    The main problem I have with this and 1000 year rain event is you should never claim something longer than the data is long. It doesn’t matter how it compares with recent years statically, there is no way to know that it could have occurred nearly every 20 years 500 years ago for a century, but nobody knows.
    Like the Met Office when they claim numerous year events they never go longer than the period of the data record is because this is the way scientists should behave and not make something up, that can’t be backed up because the data isn’t long enough to confirm it. The rain event was 1 in how long the data record is and no more because who knows? NOBODY.

    • Very good point. Any statistical projection on data from , say, the last 100y of records can only reflect the climate of that period. We know that climate was much colder during the LIA and warmer 1000y ago, so projection of statistics of the last century onto the climate of the last millennium is a falsehood.
      The second issue is the two flips of a coin. One head does not make it more likely the next flip will be tails. Presenting the the 0.1% statistic as a “1000y storm” will CERTAINLY invite the conclusion in the mind of Joe Public that we should not see another one for a thousand years.
      In short this not only bad science but wilful misdirection.

      • Patterns of weather often come in successive periods, so that is another reason why the 1000 year event is nonsense.

    • simple, it has been just as hot and it is a well known fact that we have been having 1000y storms everywhere for the last 18 years.
      /sarc

  27. “Why do you think people have been calling it a 1000-year flood?” The answer is that this headline is the initial propaganda that the public remembers. Later scientific rebuttals of the cause being global warming or CAGW pass right over their heads, even if they did notice them. It is now all just a propaganda war. Science went out the door long ago.

    • If it was a normal sunny weekend, people would have died. Considering the flood depth and extent I think they did well. So the question really is, how good was the reporting of the flood event?

      • The reporting engaged and excited many people. Not the sort of stuff Perry White would have approved of, but, by today’s standards, it was great reporting.

  28. There still seems to be confusion among the media and even folks here as to the difference between a 1000 yr flood event vs 1000 yr rainfall event. The USGS article mostly addresses flood events…but it does state that it could’ve been a 1000 yr rainfall event. NOAA apparently claimed it was a 1000 yr rainfall event.
    And a 1000 yr rainfall event can be over various durations…1 hr, 2 hrs, 24 hrs, 48 hrs, 72 hrs, etc. So obviously “a 1000 yr event” should happen more than 1 in 1000 yrs in a given location.
    And while it’s fair to use statistics and curve-fitting to estimate a 1000 yr rainfall event based on 100+ years of rainfall data, you won’t find any legit engineers or scientists standing by those figures. It’s too much of an extrapolation and has way too much error associated with it.

  29. Pay attention to how opportunistic SC is compared to a state like NY. The conversation about USGS historical flooding is fun, but the real stuff of interest is what will SC take from the feds as compared to a State and city like NYC.
    NYC is already capitalizing on Sandy by receiving additional flood protection money due to climate projections.
    What will SC do ?

  30. You build on a known flood plain, and are then surprised when you get flooded out? Is the human species really getting that dumbed down?

  31. It might have been a 1/1000 year event for that location but not for the planet or even the country. Every year a 1/1000 year event will happen somewhere and in 999 other locations it won’t. This is the fallacy of the stats and the misinformation of the media who report them.

  32. comprehensive, readable, convincing – enriching.
    Thanks for Dr. Robert Holmes and USGS.
    Regards – Hans

  33. In the same time as the South Carolina flooding, there was a similar flooding though on a smaller area in the region of Cannes, french Riviera. 17 people died. And the same voices began to blame this flooding on the climate change saying it was “unprecedented” from man’s memory.
    I am living on the mediterranean coast about 150 km west from Cannes. There is a carved mark on the wall of our city Hall that recorded the water level, about 6 ft high, of a flooding that occured on oct 19th 1858. The city Hall is located less than 100 meters from the sea shore (!), so it is difficult to imagine the huge water amounts the storm brought that day since there is no river in the vicinity.
    Indeed, never a similar flood happened again since 1858 until now.
    Never say “unprecedented”.

  34. With 263 major river basins, there is a one in a 1000 year flood in one of them every 4 years on average.
    Even if this were a 1 in a 1000, hmmpf.

  35. Wha…? April Fool’s Day? No, it’s October. Alternate universe? Maybe. It IS very hard to believe that a government agency, even one formerly dedicated to science and truth, would dare defy climate doomsayers and purveyors of apocalyptic propaganda by distributing a statement composed of scientifically defensible concepts and common sense.
    Or perhaps I’ve simply lost touch with reality and imagined this article.

  36. The rainfall event although bad enough was nothing to numerous regions around the world that get far more rainfall on a yearly, monthly and daily basis.
    The U.N. WMO (World Meteorological Organization) recently announced (2014) that a ‘new’ world record for a 48-hour (or two day) period has been confirmed following an investigation by a group of climatologists from around the world. The figure is said to be an amazing 2,493 mm (98.15”) at Cherrapunji, India that fell on June 15-16, 1995.
    The difference between 17 inch and 20 inch relatively, may be only a couple more hours of extremely heavy rain. Just put this into perspective, although it was rare for a local region many areas around the world have received greater rainfalls. Who’s to say it’s not this regions turn for some greater falls this century, when the data record only represents mainly one century out of last ten thousand years from the recent past during the current inter-glacier.
    The past century could have been easily one of driest over the past 10,000 years.

    • “…The rainfall event although bad enough was nothing to numerous regions around the world that get far more rainfall on a yearly, monthly and daily basis…”
      That’s why each location has its own criteria for what makes it a 1,000 year event. Cherrapunji averaged 129 inches of rain in July from 1971-1990 and 464 inches per year. Charlestown, SC, is around 5.4 inches and 44 inches, respectively. What constitutes a 1000 yr rainfall event in Charlestown isn’t the same as that of Cherrapunji.
      And the difference between a 17 inch and a 20 inch rain event can be huge over a large area. That 3 inches is 7% of Charlestown’ average annual rainfall. And it’s not falling on unsaturated ground.
      “Only a couple more hours of extremely heavy rain” turning a 17 inch rain event into a 20 inch one makes a huge difference.

      • …not to mention that this was over a 2-3 day period, not a monthly or yearly basis. And you’d be hard pressed to find “numerous regions around the world that get far more rainfall on a…daily basis.” Cherrapunji’s wettest month averages 4.3 inches/day.

    • Nothing makes it a 1000 year event, until you know over a 1000 years that it is the wettest weather event. Of course locations have there own mean standards compared to extremes, but my point is only over a tenth of the period leaves a lot of room for variation when compared to a unknown nine tenths of the period.
      What I mean if the same weather event occurred again even if it had been 200 years ago, it would only need to last a bit longer to cause significant difference. A mean of weather over a month has been a generally pointless statistic because it is often the result from average of extremes. Places rarely experience average weather every single day for the entire month.
      http://listdose.com/top-10-rainiest-places-on-earth/
      Daily basis I really meant like 2/3 days like experienced by this event. Cherrapunji average is very misleading because monsoons make them very variable and 98.15 inches over just 2 days is an awful amount of rainfall. Charlestown had a awful lot of rainfall compared to usual there, but it was no more than a 100+ year event based on the length of the data.

  37. Use of porous concrete can help with these floods, it can’t be used in high traffic areas like a highway, but could be used on the shoulders. It costs more than asphalt, but a little long term thinking might be required from our civil engineers.

    • Engineers don’t pay the added costs upfront or with maintenance. Bureaucrats do.
      I’ve seen impressive demos of porous concrete, but this sort of rain event is overwhelming. And rapid infiltration to the subsurface is only good until the ground becomes saturated.

  38. ” So, rather than someone saying this was a 1000-year flood, it is more accurate to say that “statistically speaking”, the rainfall that fell was a 1000-year rain storm, although it did not result in a 1000-year flood.”
    Climate change won’t cause a thousand year flood directly, it will cause the conditions that create the thousand year flood. The rainfall is the fingerprint, not the flooding, which will vary depending on numerous other variables.

  39. This piece of news alert in relation to historic floods in Carolina, US , in the first week of October 2015 was circulated about 12 days back by this Vedic astrology writer though the prediction of this writer was in existence since June last:- October 2015 has just begun. News reports suggest that a powerful hurricane Joaquin is wanting to lash US coastal areas. It seems concerned officials in US have advised residents in places likely to be affected to be in preparedness. In this regard , this Vedic astrology writer wants to agree with the concerned officials while emphasizing that astrologically speaking, it is advisable to be fully prepared to face the hurricane Joaquin in coming days in US coastal areas or nearby States which usually has an impact. This writer’s prediction about danger from strong storms or sea tsunamis in vulnerable areas near some islands located near sea to come in October 2015 was published in article – Total lunar eclipse of 28 September 2015 and world – in the Summer 2015 ( June) issue of The Astrologer’s Notebook , a quarterly publication from North Port , Florida. Just reproducing the related parts from the article : -“During second half of 2015 , among other things , dangers from sea or in sea like strong storms or sea tsunamis could be likely in vulnerable regions. Power dams and electricity could bring to surface substantial concern. Natural calamities such as floods , landslides and earthquake could sadden.” The prediction further goes in the same article : “ Some islands located near the sea may need to take some precaution .Though second half of 2015 seems to be causing concern , months October and November of 2015 are likely to trigger many unwelcome things out of above mentioned aspects or areas of life”.
    The unique contribution by way of appropriate , accurate and well- timed contribution of this writer in alerting the concerned people deserves to be noted.

Comments are closed.